Enclosed circuit interrupting structure with improved latching mechanism



Sept. E2, l967 5- \|\'1|=[;|\1|\1,L\ ETAL 3,341,672

ENCLOSED CIRCUIT INTERRUPTING STRUCTURE WITH IMPRCVED LATCUING MECHANISM Figi Fi g8.

Sept. 12, 1967 5 A. MRENNA ET AL 3,341,672

ENCLOSED CIRCUIT INTERRUPTING STRUCTURE WITH IMPROVED LATCHING MECHANISM Original Filed March 13, 1964 3 Sheets-Sheet 2 Sept 12, 1967 5. A. MRENNA ETAL 3,341,672

ENCLOSED CIRCUIT INTERRUPTING STRUCTURE WITH IMPROVE!) LA'ICHING MEGHANISM Original Filed March 13, 1964 5 Sheets-Sheet 5 INVENTORS S'rephen AA Mrennu und Howard E. Reichert ATTORNEY Patented Sept. 12, 1967 3,341,672 ENCLOSED CIRCUIT INTERRUPTING STRUC- TURE WITH IMPROVED LATCHING MECH- ANISM Stephen A. Mrenna and Howard E. Reichert, Beaver, Pa.,

assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Original application Mar. 13, 1964, Ser. No. 351,725, now Patent No. 3,278,710, dated Oct. 11, 1966. Divided and this application Mar. 1, 1966, Ser. No. 530,922

8 Claims. (Cl. 20th-5th) This application is a division of our parent application, Ser. No. 351,725, filed Mar. 13, 1964, now Patent No. 3,278,710.

This invention relates ygenerally to circuit interrupting devices and more particularly to enclosed safety switches.

An object of this invention is to provide an enclosed switch structure with improved latching means providing a safer switch installation.

Another object of this invention is to provide an improved enclosed safety switch with a defeatable latch member that is automatically moved into a latching position to latch the cover closed when the cover is moved to the close-d position which defeatable latch member opcrates automatically to latch the switch open when the switch is open and the cover is moved to the open position.

A general object of this invention is to provide an improved relatively inexpensive and compactly constructed enclosed safety switching device.

The novel features that are considered characteristic of this invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description when read in conjunction with the accompanying drawings.

In said drawings:

FIGURE l is a plan view, with parts broken away, of an enclosed switching device embodying principles of this invention;

FIG. 2 is a partial plan view, with the cover and certain other parts broken away, of the enclosed switching device seen in FIG. l;

FIG. 3 is a sectional view taken generally along the line III--III of FIG. 2;

FIG. 4 is a partial sectional view taken generally along the line IV-IV of FIG. 2;

FIG. 5 is a view similar to FIG. 4 showing the switch operating mechanism in the closed position; `and FIGS. 6, 7 and 8 are partial views illustrating certain operating positions of the latching means of this invention.

Referring now to the drawings, there is shown, in FIGS. 1 and 2 an enclosed safety switch 3 comprising an enclosure 5 and a switching device 7. The enclosure 5 comprises a receptacle 9 (FIG. 7) and an openable cover 11. The receptacle 9 comprises a sheet metal base 13 an-d four sheet metal side walls 15 extending up from the base to form an opening at the front of the receptacle. The cover 11 is pivotally supported on hinges 17 (FIG. 1) to enable the recept-acle 9 to be opened and closed in a manner well known in the art.

Referring to FIGS. 2 and 3, the switching device 7 comprises a switch structure 19 and an operating mechanism 21. The switch structure 19 comprises a unitary insulating base or support member 23 that is iixedly secured to the enclosure base 13 by suitable securing means.

As can be seen in FIG. 2, the switch structure 19 cornprises three similar pole units disposed in a generally sideby-side relationship. Each of the pole units comprises a rst fuse clip 25 that is secured to the insulating support 23 by means of a bolt 2.7 and nut 29. The bolt 27 and nut 29 also secure a terminal device indicated generally at 31 to the insulating support 23. The terminal device 31 is a conducting structure comprising an elongated part 33 that has an opening therein through which the bolt 27 passes. The terminal device 31 also comprises a block part 35 having a generally horizontal end opening 37 (FIG. 3) therein and a vertical tapped front opening therein into which a threaded pressure securing member 39 is screwed.

Each pole unit of the switch device also comprises a fuse clip 41 that is supported to the insulating support 23 by means of a screw 43. A fuse, indicated in broken lines, is clipped into each pair of fuse clips 25, 41 in a wellknown manner. Each pole unit also comprises a conducting contact support clip 47 that is secured to the insulating block 23 by means of a screw 49. A con-ducting strip 51 is secured in place by means of the screws 43 and 49, to electrically connect each fuse clip 41 with the associated contact support clip 47. A generally liat conducting movable contact member 53 is pivotally supported on each of the contact supports 47 by means of a pivot pin 55. Each of the three moving contact arms 53 is xedly secured to a common insulating tie bar 57 by suitable securing means. In between eacli pair of adjacent contact arms 53, a metallic bifurcated connecting member 61 is iixedly secured to the common insulating tie bar 57. An operating rod 63 is disposed lwithin the bifurcations of each of the two connecting members 61. The operating rod 63 is movable between two operating positions to operatively move the common tie bar 57 to simultaneously pivot all three of the movable contact members 53 to the open and closed positions in a manner to be hereinafter more specifically described.

In each pole unit, the ilat knife-blade type contact 53 cooperates with a generally U-shaped stationary contact 67 that comprises two spaced generally resilient conducting legs that resiliently engage the opposite ilat sides of the associated contact arm 53 in the closed position of the contacts. Each stationary Contact 67 is secured to the insulating support 23 by means of a screw 69 and nut 71 that serve to bias a plate 73 into engagement with a front surface of the support 23 to secure the stationary contact 67 and a terminal structure 75 to the front of the support 23. Each pole unit is provided with a terminal structure 75 that is constructed similar to the previously described terminal structure 31. For this reason, the saine specific reference characters are used to identify parts of both of the terminals 31 and 75. In each pole unit, the stationary contact structure 67 and terminal structure 75 are secured together by means of a screw 77 that passes through an opening in the base of the contact 67 and through an opening in the conductingv extension 33 of the terminal structure 75 to be threaded into a tapped opening in a conducting plate 73.

A common insulating arc-shield or arc-hood structure 79 is supported on the front of the insulating support 23. The insulating arc-hood structure 79 (FIGS. 2 and 3) comprises a unitary insulating block 80 formed with three arc-hoods 81 each of which arc-hoods forms a cavity 83. A recess is provided between each pair of adjacent arc-hoods 81. A mounting screw 87, which is disposed in each of the recesses passes through an elongated slot 88 in the insulating block 8l. Each of the `screws 87 is threaded into a tappe-d opening in the supporting block 23 whereby the two screws 87 secure the arc-hood structure 79 to the insulating support 23. As is seen in FIG. 3, an opening 91 is provided in each of the arc-hoods 81 to vent the gas from the arc-hood cavity 83.

As is best seen in FIG. 2, a relatively narrow slot 95 is provided in the front of each of the arc-hoods 81 of the arc-extinguishing device 79 to permit movement of the associated knife-blade type contact 53 into and out of the associated arc-hood cavity 83 so that the contact can be moved into and out of engagement with the associated stationary contact 67. The insulating arc-extinguishing device 79 disclosed in FIGS. 2 and 3 comprises three insulating cavities 83 in which three arcs are drawn and extinguished when the switch is operated to the open position. The arc gases are forced out of the cavities 83 under pressure through the openings 91.

Referring to FIGS. 2, 4 and 5, the operating rod 63 is operated to simultaneously operate the three movable contacts 53 by operation of the operating mechanism 21. The operating rod 63 is a generally U-shaped member that is pivotally supported on the opposite side walls of the receptacle 9. As can be seen in FIG. 2, one leg of the operating rod 63 is pivotally supported on a pin 121 and the otherleg is pivotally supported on a pin 123. The operating rod 63 is operated by operation of an actuating member 125 (FIGS. 4 and 5) that is also pivotally supported on the pin 123. The actuating member 125 has two projections 127 and 129 that extends from the main plane of the generally at member 125 and engage one leg of the operating rod 63 to move the rod in a manner to be hereinafter specifically described. Snap action of the operating mechanism is effected by means of a compression spring 131 that is supported on a rod structure 133 that is pivotally supported at one end on the actuating member 125 by means of a pin 135. The other end of the rod structure 133 protrudes through an opening in a flange 137 of a stationary supporting bracket 139. The bracket 139 is rigidly supported on the side wall of the receptacle by means of rivets 141 and 143. As can be seen in FIG. 2, spacers 145 and 147 are provided on the rivets 141 and 143 respectively to space the bracket 139 relative to the receptacle side wall 15. A generally flat operating member 151 protrudes through an opening 153 (FIG. 1)

in the cover 11 and an external operating handle 155 (FIGS. 1 and 2) is provided on the operating member 151 to permit manual operation of the switching device when the cover 11 is in either the closed or opened position. The member 151 has an elongated opening 152 therein to receive the hasps of from one to three padlocks which may be used to lock the member in the off position and, if the cover is closed, to lock the cover in the closed position. As can be seen in FIGS. 4 and 5, the member 151 is pivotally supported on the pivot pin 123 and a projection 161, that is bent-over at the bottom of the member 151, is disposed between two leg portions 163 and 165 on the actuating member 125. Two bent-over projections 1619 and 171 are provided on the supporting bracket 139 to limit movement of the operating rod 63 in the two operating positions. As is seen in FIGS. 4 and 5, the extension 161 protrudes through an opening 175 in the stationary bracket 139.

The switch operating mechanism is shown in the on or closed position in FIG. 5. When the switch is connected and in the closed position, the circuit in each pole unit extends from a line conductor (not shownl in FIG. 2) that would be attached to the solderless terminal connector 75 by means of the screw-type connector 39, through the conducting strip 33, the stationary contact 6.7, the movable contact 53, the conducting contact support 47, the conductor 51, the fuse clip 41, the fuse 45, the fuse clip 25, the conducting strip portion 33 of the terminal connector 31, the load terminal connector 31, to the conductor (not shown) that would be connected to the load terminal connector 31 by means of the screw type connector 39'.

In order to operate the switch to the open-circuit position (FIGS. 2-4), the external operating handle 155 (FIG. 2) is rotated from the on to the off position to rotate the operating member 151 in a clockwise (FIG. 5) direction about thepivot 123. During this motion, the projection 161 on the operating member 151 engages the foot 163 on the actuating member 125 to rotate the actuating member in a clockwise (FIG. 5) direction about the pivot 123 during which motion the operating rod 133- is moved from the FIG. 5 to the FIG. 4 position. As the member 133 is moved from the FIG. 5 to the FIG. 4 position, the spring 131 is initially compressed and then it passes an over-center position to discharge to move the parts to the FIG. 4 position with a snap-action. As the member 125 moves from the FIG. 5 to the FIG. 4 position, the extension 127 on the member 125 engages the leg of the operating rod 63 to move the operating rod 63 in a clockwise (FIG. 5) direction about the pivot 123 to the oif or open circuit position in which it is seen in FIG. 4. In order to close the switch structure, the operating member 151 is rotated in a counterclockwise direction whereupon the extension 161 engages the leg 165 of the actuating member 125 to pivot the actuating member 125 counterclockwise about the pivot pin 123 from the FIG. 4 to the FIG. 5 position during which movement the over-center spring 131 is actuated to the FIG. 5 position to move the member 125 to the FIG. 5 position with a snap-action. As the member 125 moves from the FIG. 4 to the FIG. 5 position, the extension 129 thereon engages the leg of the operating rod 63 to rotate the rod 63 in `a counter-clockwise direction to the closed position seen in FIG. 5.

Referring to FIGS. 2 and 3, when the operating rod 63 is moved to the off or open position, the rod 63 moves the two connecting members 61 to thereby move the insulating tie bar 57 to thereby simultaneously pivot the three movable contacts 53 about the pivots 55 to the open position seen in FIGS. 2 and 3. When the operating mechanism is operated to the on or closed position, the operating rod 63 is moved to move the tie bar 57 to simultaneously pivot the three movable contacts 53 .about the pivots 55 to the closed position in which position each of the knife-blade type movable contacts is disposed between and engages the resilient twin conducting members of the stationary clip-type contact structure 67 in a manner well known in the art.

When the switch is operated to the off position to open a circuit .an arc is drawn between each movable contact 53 and the associated stationary contact 67 which arc will be extinguished within the associated arc-hood of the arc-extinguishing structure 79. The gases generated during extinction of the arc are expelled at the end of the breaker in each pole unit through the associated opening 91.

Referring to FIGS. 1 and 2, it will be noted that the receptacle part of the enclosure is opened at the front by pivotal movement of the cover 11 about the hinges 17.

Referring to FIGS. l and 6-8, a resilient cover latching member 191 is welded or otherwise rigidly secured to one of the internal side walls of the receptacle 9 and it is bent over at 193 (FIG. 7) so that the main part thereof is disposed along a plane that is parallel to and spaced from the side wall to which the member is secured. As can be seen in FIG. l, the cover 11 has an opening or elongated slot 195 therein and the generally resilient cover latch 191 is provided with a tang portion 197 bent over and formed in the member by means of a stamping operation. When the cover 11 is moved to the closed position, the cover engages the tang 197 to flex the resilient member 191 and when the cover reaches the fully closed position the resilient member 191 snaps back into the latching position wherein the tang 197 is disposed over a portion of the cover to latch the cover in the closed position. An opening 199 is provided in the latch 191 to receive the hasp of a padlock so that the cover can be padlocked in the closed position. When it is desired to open the cover, if there is a padlock secured to the member 191, the padlock is removed and the member191 is manually flexed to a position'aligning the tang 197 with the cover opening 195 `and the cover is then pivoted to the open position.

There is shown, in FIGS. 4 and 5, a latching member 201 comprising a unitary sheet-metal type member formed with a supporting leg 203 having a pivot pin 205 thereon that extends through an opening in the sidewall to pivotally support the member 201 on the one side wall 15 of the receptacle 9. The unitary latch member 201 is provided with a projecting part 207 that is disposed adjacent a slot 209 in the upper part of the side wall 15. The latching member 201 is also provided with a lirst latching part 213 that is bent over from the plane of the part 207 (FIG. 1) which part 213 has an opening 215 therein for a purpose to be hereinafter specifically described. The latching member 201 is also provided with a second latching part 217 thereon bent over and extending out of the plane in which the part 207 is disposed (FIGS. 4, 5 and l). As can be seen in FIG. 4, when the switch is in the olf or open circuit position7 and the enclosure cover is in the open position, a torsion spring 221 that is fixed at one end in a part 222 of the side wall 15, and that engages the projection 217 at the other end thereof, biases the latching member 201 in a clockwise (FIG. 4) direction to move the latching part 217 into a notch 225 in the operating member 151 so that if there is an attempt to move the operating member 151 from the olf to the on" position, the latching part 217 will engage a ledge 227 on the operating member 151 to prevent this operative closing movement of the operating member 151. As can be seen in FIG. 4, the pivot 205 is to the left of the line of action between the part 227 of the member 151 and the latching part 217 of the latch member 201 so that the force of rotation of the member 151 will operate through pivot 205 preventing movement of the operating member 151 to the on or circuit closed position. Referring to FIGS. 1, 7 and 8, the cover 11 is provided with a flange part 231 and a pin 233 is welded or otherwise rigidly secured to the flange part 231. When the cover 11 is pivotcd to the closed position, the pin 233, that is secured to the cover, moves into the slot 209 (FIGS. 4, 5 and 6) in the side wall 15 and engages the projecting portion 207 of the latch member 201 to rotate the latch member against the bias of the torsion spring 221 to a position wherein the latching projection 217 clears the notch 225 so that when the cover 11 is moved to the closed position, the switch operating member 151 can be freely operated between the on and the oli positions. If the circuit interrupter is oft when the cover 11 is moved to the open position, the pin 233 will release the portion 207 whereupon the spring 221 will automatically move the member 201 back to the latching position seen in FIG. 4. If the circuit interrupter is on or closed when the cover is moved to the open position, the spring 221 will move the latching member 201 to a position wherein the projection 217 engages the outer surface or edge 234 of the member 151 so that, if the switch is thereafter moved to the off position, the spring 221 will automatically snap the member 201 back to the latching position seen in FIG. 4 when the edge 227 clears the projection 217. Thus, the circuit interrupter will again be latched in the off position.

Referring to FIG. 4, the parts are shown therein with the switch olf and the cover open. When the cover 11 is moved into the closed position, the pin 233 (FIGS. 1 and 6 8) that is attached thereto engages the projection 207 (FIG. 4) to rotate the member 201 to clear the latch part 217 from the notch 225 of the operating member 151 in the manner hereinbefore described. As the latch member 201 rotates, the extension or latching projection 213 thereon moves over top of the pin 233 to the position seen in FIG. l. If the enclosed switch is in the oli position and the cover is moved to the open position, as the pin 233 moves away from the part 207 (FIG. 4) the torsion spring 221 will rotate the latch 201 to the position seen in FIG. 4 and the extension 213 will be rotated out of the latching position over top of the pin 233 so that the pin 233 and cover 11 will be readily moved to the open position. If, however, the switch is moved to the on or closed position when the cover is in the closed position, the extension or projection 217 on the member 201 will engage the outer edge 234 of the member 151 so that the spring 221 will not lbe able to rotate the latch member 201 to the unlatching position seen in FIG. 4 and the projection 213 will overlie and engage the pin 233 (FIG. l) to prevent opening of the -cover 11 when the switch structure is in the on or closed position. An authorized worker will readily know how to defeat this latching function. As can be seen in FIGS. 7 and 8, the pin 205, which is pivotally supported in an opening in the side wall 15 and to which the latch member 201 is attached, has an external sl-ot therein to receive a screw driver or other tool. Thus, when the switch and cover are both closed, an authorized worker can rotate the member 201 to a position wherein the opening 215 (FIG. 1) is aligned with the pin 233 and the worker can then release the latch 191 and pivot the cover to the open position with the pin 233 moving through the opening 215 (FIG. 1) of the latch member 201. With the torsion spring 221 biasing the latch 201 into the latching position, it can be understood that a worker will hold the latch 201 with one hand and operate the cover latch 191 with the other hand to release the cover 11 so that the cover 11 can be operated to the open position.

The cover 11 can be moved into the closed position when the enclosed switch is in the on position. When the parts are in the position seen in FIG. 5, the cover is open and the switch is in the on or closed position. If the cover 11 is moved to the closed position, the pin 233 on the cover will engage the top of the projection 213 and pivot the latch member 201 in a counterclockwise (FIG. 5 direction against the bias of the spring 221 until the pin 233 is aligned with the opening 215 (FIG. l) whereupon the pin will move through the opening 215 as the cover is moved into the closed position, and when the cover has reached the closed position the spring 221 will automatically move the latch 201 in a clockwise (FIG. 5) direction back to the latching position which clockwise latching movement will be stopped by engagement of the projection 217 against the edge 234 of the operating member 151. The projection 213 will then be disposed over the pin 233 (FIG. 1) to again latch the cover in the closed position in the same manner as hereinbefore described.-

From the foregoing, it can be understood that the invention comprises an improved latch comprising a unitary pivotally supported spring biased member that Serves to defeatably latch the switch in the oli or open position when the enclosure cover is opened and to defeatably latch the enclosure -cover closed when the switch is in the on or closed position and the cover is in the closed position. When the enclosure cover is opened and the switch is closed, the cover can be moved into the closed position during which movement the latch member will be cammed to a position permitting closing of the cover, and when the cover reaches the closed position the latching member will automatically be moved to a position latching the cover in the closed position. When the cover is in the closed position, the enclosed switch can be freely manually operated by means of the external operating handle. The operating member is also provided with means for receiving at least three padlocks to permit the switch to be padlocked in the open position. If the switch is padlocked in the open position with the enclosure cover closed, this padlocking operation will also serve to lock the cover in the closed position. The enclosure is also provided with a resilient cover latch that is spaced from the pivotally supported latch and that must be operated in order to permit the cover to be opened. Since the two latch members are in a spaced relationship and because they are both spring biased toward the latching position, a worker must operate both of the latch members simultaneously in order to effectively unlatch the cover for a cover opening operation. Thus, it is less likely that an unauthorized person will be readily able to either accidentally or intentionally open the enclosure cover. The resilient latching member also has an opening therein for receiving a padlock to permit the cover to be padlocked in the closed position.

While the invention has been disclosed in accordance with the provisions of the patent statutes, it is to be understood that various changes in the structural details and arrangements and parts may be made without departing fromsome of the essential features of the invention. It is desired, therefore, that the language of the appended claims be given as reasonably broad an interpretation as the prior art permits.

We claim as our invention:

1. An enclosed control structure comprising an enclosure, said enclosure comprising a receptacle having a receptacle opening, an openable cover structure supported on said receptacle and movable to open and close said receptacle opening, a control device supported within said receptacle and comprising a pair of cooperable contacts, an externally operable operating member operable to an olf position to open said contacts and to an on position to close said contacts, a latch member pivotally supported on a fixed pivot on said receptacle, resilient means biasing said latch member in a iirst pivotal direction toward a rst position, with said operating member in the oit position and said cover structure in the open position, said resilient means maintaining said latch member in said rst position wherein said latch member is in the path of movement of said operating member to engage said operating member to prevent operation of said operating member to the on position, when said operating member is in the off position and said cover structure is moved to the closed position, said cover structure engaging said latch member and pivoting said latch member against the bias of said resilient means in a second pivotal direction opposite said iirst pivotal direction to a second position, said latch member in said second position being out of the path of movement of said operating member whereby said operating member can be freelymoved to the on position when said cover structure is in the closed position, when said cover structure is in the closed position and said operating member is moved to the on position said operating member being in the path of movement of said latch member to engage said latch member to prevent movement of said latch member in said iirst pivotal direction to said rst position, said latch member and said cover structure being constructed and arranged such that when said cover structure is moved toward the open position with said operating member in the on position said cover structure engages said latch member tending to pivot said latch member in said rst pivotal direction toward said first position which pivotal movement of said latch member is restrained by the engagement of said latch member with said operating member whereby said engagement of said latch member with said cover structure prevents opening movement of said cover structure.

Z. An enclosed control structure according to claim 1,

and when said cover structure is moved toward the open position with `said operating member in the ofi position said latch member pivoting in said rst pivotal direction to said iirst position during which movement said latch member releases said cover structure whereby said cover structure can be moved to the open position when said operating member is in the olf position.

3. An enclosed control structure'according to claim 1, said latch member being movable in said second pivotal direction from said second position to a third position when said operating member is in said on position, said latch member in said third position being out of the path of movement of said cover structure whereby said cover structure can be opened when said operating member is in said on position and said cover structure is in the closed position, and said latch member being externally operable to said third position when said operating member is in said on position and said cover structure is in the closed position.

4. An enclosed control structure according to claim 2, and externally accessible means operable to move said latch member in said second pivotal direction to a third position out of the path of movement of said cover structure when said operating member is in said on position.

5, An enclosed control structure according to claim 1, said receptacle comprising a generally planar base and side wall means extending from said base generally normal to said base to form said receptacleopening at the front of said receptacle, and said latch member being pivotally mounted on said side wall means.

6. An enclosed control structure according to claim 4, said receptacle comprising a generally planar base and side wall means extending from said base in a direction generally normal to the plane of said base to form said receptacle opening at the front of said receptacle, and said latch member being pivotally mounted on said side wall means.

7. An enclosed control structure according to claim 2, said receptacle comprising a generally planar base and side wall means extending from said base generally normal to the plane of said base to form said receptacle opening at the front of said receptacle; said latch member being pivotally mounted on said side wall means; said latch member comprising a member supported for unitary movement and comprising a rst part, a rst latch part and a second latch part; said cover comprising a cover latch part; in said rst position said rst latch part of said latch member being in the path of movement of said operating member; upon a closing operation of said cover structure said cover latch part engaging said rst part of said latch member and pivoting said latch member to said second position; and in said second position said second latch part of said latch member overhanging said cover latch part to prevent opening of said cover structure.

8. An enclosed control structure according to claim 7, and externally operable means operable when said operating member is in said on position and said cover structure is in said closed position to move said latch member in said second pivotal direction to a third position wherein said second latch part of said latch member is free of said cover latch part to permit movement of said cover structure to the open position when said operating member is in said on position.

References Cited UNITED STATES PATENTS 3,028,459 4/ 1962 Norden 200--50 3,054,866 9/ 1962 Rexroad 200-50 3,171,908 3/1965 Malota 200-50 3,213,218 10/1965 Herrmann et al. 200-50 3,213,224 10/ 1965 Mrenna et al. 200-50 3,238,341 3/1966 Haydu 200-16 X 3,278,710 10/1966 Mrenna et al 200-50 X ROBERT K. SCHVAEFER, Primary Examiner. I. R. SCOTT, Assistant Examiner. 

1. AN ENCLOSED CONTROL STRCUTURE COMPRISING AN ENCLOSURE, SAID ENCLOSURE COMPRISING A RECEPTACLE HAVING A RECEPTACLE OPENING, AN OPENABLE COVER STRUCTURE SUPPORTED ON SAID RECEPTACLE AND MOVABLE TO OPEN AND CLOSE SAID RECEPTACLE OPENING, A CONTROL DEVICE SUPPORTED WITHIN SAID RECEPTACLE AND COMPRISING A PAIR OF COOPERABLE CONTACTS, AN EXTERNALLY OPERABLE OPERATING MEMBER OPERABLE TO AN "OFF" POSITION TO OPEN SAID CONTACTS AND TO AN "ON" POSITION TO CLOSE SAID CONTACTS, A LATCH MEMBER PIVOTALLY SUPPORTED ON A FIXED PIVOT ON SAID RECEPTACLE, RESILIENT MEANS BIASING SAID LATCH MEMBER IN A FIRST PIVOTAL DIRECTION TOWARD A FIRST POSITION, WITH SAID OPERATING MEMBER IN THE "OFF" POSITION AND SAID COVER STRUCTURE IN THE OPEN POSITION, SAID RESILIENT MEANS MAINTAINING SAID LATCH MEMBER IN SAID FIRST POSITION WHEREIN SAID LATCH MEMBER IS IN THE PATH OF MOVEMENT OF SAID OPERATING MEMBER TO ENGAGE SAID OPERATING MEMBER TO PREVENT OPERATION OF SAID OPERATING MEMBER TO THE "ON" POSITION, WHEN SAID OPERATING MEMBER IS IN THE "OFF" POSITION AND SAID COVER STRUCTURE IS MOVED TO THE CLOSED POSITION, SAID COVER STRUCTURE ENGAGING SAID LATCH MEMBER AND PIVOTING SAID LATCH MEMBER AGAINST THE BIAS OF SAID RESILIENT MEANS IN A SECOND PIVOTAL DIRECTION OPPOSITE SAID FIRST PIVOTAL DIRECTION TO A SECOND POSITION, SAID LATCH MEMBER IN SAID 